Reaction mass of 6-(butan-2-yl)quinolone and 8-(butan-2-yl)quinoline

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Ames test (OECD TG 471): Negative

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

September 19, 2003 - October 24, 2003

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Reliability 1 is assigned because the study is conducted according to OECD TG 471, in compliance with GLP, without deviations that influence the quality of the results.

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

(1997)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)

Version / remarks:

(2000)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Target gene:

- S. typhimurium: Histidine gene

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Metabolic activation:

with and without

Metabolic activation system:

Rat liver S9-mix induced by a combination of phenobarbital and ß-naphthoflavone

Test concentrations with justification for top dose:

- Dose range finding test:
TA 1535, TA 1537, TA 98, TA 100 and TA 102 (without and with S9): 50, 158, 500, 1580 and 5000 µg/plate

- Experiment 1:
Due to cytotoxicity (in all strains), the following dose levels were used:
TA 1535 (without S9): 500, 250, 125, 62.5 and 31.3 µg/plate
TA 1535 (with S9): 125, 62.5, 31.3, 15.6, 7.81 and 3.91 µg/plate
TA 1537, TA 98 and TA 102 (without S9) and TA 98 (with S9): 250, 125, 62.5, 31.3, 15.6 and 7.81 µg/plate
TA 102 (with S9): 250, 125, 62.5, 31.3 and 15.6 µg/plate
TA 100 (without and with S9) and TA 1537 (with S9): 500, 250, 125, 62.5, 31.3 and 15.6 µg/plate

- Experiment 2:
Due to the absence of cytotoxicity in the presence of S9 with the strains TA 1535, TA 98 and TA 102, additionally the following dose levels were used:
TA 1535 (with S9): 500, 250, 125, 62.5, 31.3 and 15.6 µg/plate
TA 98 and TA 102 (with S9): 1000, 500, 250, 125, 62.5 and 31.3 µg/plate

- Experiment 3 (the independent repeat):
TA 1535 and TA 102 (without and with S9) and TA 1537 (without S9): 250, 125, 62.5, 31.3, 15.6, 7.81 and 3.91 µg/plate
TA 98 and TA 100 (without and with S9) and TA 1537 (with S9): 250, 125, 62.5, 31.3, 15.6 and 7.81 µg/plate

- Experiment 4:
As TA 100 showed an increase at 31.3 µg/plate in the presence of S9, out of the historical control range (but not fulfilling the criteria for a positive response), a fourth experiment was performed:
TA 100 (with S9): 62.5, 31.3, 15.6, 7.81 and 3.91 µg/plate

Vehicle / solvent:

- Solvent used: DMSO
- Justification for choice of solvent: the test substance was found to be soluble in DMSO up to 5000 µg/plate

Untreated negative controls:

yes

Remarks:

(untreated plates)

Negative solvent / vehicle controls:

yes

Remarks:

(50 or 100 µL/plate DMSO)

Positive controls:

yes

Positive control substance:

other: see section "Any other information on materials and methods incl. tables"

Details on test system and experimental conditions:

METHOD OF APPLICATION:
- Experiment 1 and 2: in agar (plate incorporation method)
- Experiment 3 and 4 (independent repeat): pre-incubation method

DURATION
- Exposure duration: 72 hours

NUMBER OF REPLICATIONS:
- Doses of the test substance were tested in triplicate in each strain (in all 4 experiments)

DETERMINATION OF CYTOTOXICITY
- Method: on the basis of a decline in the number of spontaneous revertants, a thinning of the background lawn or a microcolony formation

Evaluation criteria:

For the test substance to be considered mutagenic, two-fold (or more) increases in mean revertant numbers must be observed at two consecutive dose-levels or at the highest practicable dose-level only. In addition there must be evidence of a dose-response relationship showing increasing numbers of mutant colonies with increasing dose levels.

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: No precipitation was observed up to and including the top dose of 5000 µg/plate

RANGE-FINDING/SCREENING STUDIES:
- In all strains toxicity was observed at either 158 or 500 µg/plate and above, both in the absence and presence of S9 in the dose range finder.

COMPARISON WITH HISTORICAL CONTROL DATA:
- The negative and strain-specific positive control values were within the laboratory historical control data ranges indicating that the test conditions were adequate and that the metabolic activation system functioned properly.

ADDITIONAL INFORMATION ON CYTOTOXICITY:
- In all strains toxicity was observed at the higher doses (at >= 250 µg/plate), both in the absence and/or presence of S9

Conclusions:

Interpretation of results (migrated information):
negative

The substance is not mutagenic in the Salmonella typhimurium reverse mutation assay performed according to OECD 471 (1997).

Executive summary:

The mutagenic activity of the substance was evaluated in accordance with OECD 471 (1997) and according to GLP principles. The test was performed in two independent experiments, at first a direct plate assay was performed and secondly a pre-incubation assay, both in the absence and presence of S9-mix. The dose levels were selected based on observed cytotoxicity in all strains (>=250 ug/pl). Adequate negative and positive controls were included. The substance did not induce a significant dose-related increase in the number of revertant (His+) colonies in each of the five S. typhimurium tester strains (TA1535, TA1537, TA98, TA100 and TA102), both in the absence and presence of S9-metabolic activation. These results were confirmed in independently repeated experiments. Based on the results of this study it is concluded that the substance is not mutagenic in the Salmonella typhimurium reverse mutation assay.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

Additional information from genetic toxicity in vitro:

Ames: The mutagenic activity of the substance was evaluated in accordance with OECD 471 (1997) and according to GLP principles. The test was performed in two independent experiments, at first a direct plate assay was performed and secondly a pre-incubation assay, both in the absence and presence of S9-mix. The dose levels were selected based on observed cytotoxicity in all strains (>=250 ug/pl). Adequate negative and positive controls were included. The substance did not induce a significant dose-related increase in the number of revertant (His+) colonies in each of the five S. typhimurium tester strains (TA1535, TA1537, TA98, TA100 and TA102), both in the absence and presence of S9-metabolic activation. These results were confirmed in independently repeated experiments. Based on the results of this study it is concluded that the substance is not mutagenic in the Salmonella typhimurium reverse mutation assay.

Justification for selection of genetic toxicity endpoint
This study result of this study is reliable and adequate for covering this endpoint

Justification for classification or non-classification

Based on the results of the Ames test, Sec Butyl Quinoline does not have to be classified for mutagenicity in accordance with Regulation (EC) No. 1272/2008 and Directive 67/548/EEC.